When the Swern oxidation reaction is used to produce an aldehyde compound or a ketone compound from a primary or secondary alcohol, no waste containing a heavy metal is produced and the reaction can be widely applied to various compounds. Also no excess oxidation arises and epimerization, at the α-position with respect to a carbonyl group, does not arise. Therefore, this method is widely used as an organic synthesis reaction method.
However, the Swern oxidation reaction has a problem in that an activation reaction product of a sulfoxide compound and an intermediate of an alkoxysulfonium salt are thermally unstable and, also, by-products are likely to be produced by Pummerer rearrangement at a temperature of −30° C. or higher. To solve this problem, in a conventional method, the reaction temperature must be securely controlled to a low temperature such as −50° C. or lower. Such a low temperature reaction is expensive and requires a long reaction time and it is actually difficult to control the temperature. It is difficult to scale up this method from an industrial point of view.
As a trial using a microreactor for an organic chemical reaction, for example, Japanese Unexamined Patent Publication (Kokai) No. 2002-155007 discloses that a fine-structured reaction system is used so as to produce aldols from aldehydes and/or ketones at a temperature of −10 to +250° C. through a catalytic reaction, while Japanese Unexamined Patent Publication (Kokai) No. 2003-113185 discloses a method, for producing an allylboron compound and an alkylboron compound, which comprises reacting a lithium aromatic and an aliphatic compound with a boron compound at a temperature of −60° C. to +30° C. using a microreactor.
Furthermore, Kohyo (National Publication of Translated Version) No. 2003-506339 discloses a method for a Friedel-Crafts acylation reaction of an acylating agent and strong acid with an organic compound (preferably, an aromatic or heteroaromatic compound) in a microreactor at a temperature of 10 to 90° C. Furthermore, Japanese Unexamined Patent Publication (Kokai) No. 2003-128677 discloses a method, for producing an allylboron and an alkylboron, which comprises reacting a halide of allylmagnesium and alkylmagnesium with a boron compound in a microreactor at a temperature of −60° C. to +80° C.
However, there has never been known a method capable of industrially carrying out the Swern reaction of a primary or secondary alcohol using a microreactor.